Pump for preparing diluted liquids of predetermined degrees of dilution

ABSTRACT

A pump for preparing diluted liquids of a series of various degrees of predetermined dilutions comprises a tube made of a flexible and resilient material. The tube opens at one end into a container of a diluting liquid and is provided at its other end with a fine charging tube. At least two or more blocking devices are provided for blocking the tube, and a plurality of discharging means are provided for squeezing liquid from the tube. A branch tube extends from a base portion of the firstmentioned tube and is provided at its open end with a pipette. Through the process of blocking the first-noted tube and compressing and releasing it, a specimen in a plurality of test tubes placed in turn immediately below the fine charging tube and the pipette is sucked up and diluted successively so as to obtain a series of dilute liquids of various high degrees of dilution.

United States Patent [1 1 Mochida l PUMP FOR PREPARING DILUTED LIQUIDS OF PREDETERMINED DEGREES OF DILUTION [76} Inventor: E1 Mochida, 5-4. 2-chome,

Komagome, Toshima-ku, Tokyo, Japan {22] Filed: Apr. 10, I974 [21] Appl, No: 459,614

[ June 10, 1975 5/1973 Begg et al. 23/259 [57] ABSTRACT A pump for preparing diluted liquids of a series of various degrees of predetermined dilutions comprises a tube made of a flexible and resilient material. The tube opens at one end into a container of a diluting liquid and is provided at its other end with a fine charging tube. At least two or more blocking devices are provided for blocking the tube, and a plurality of discharging means are provided for squeezing liquid from the tube. A branch tube extends from a base portion of the first-mentioned tube and is provided at its open end with a pipette. Through the process of blocking the first-noted tube and compressing and releasing it. a specimen in a plurality of test tubes placed in turn immediately below the fine charging tube and the pipette is sucked up and diluted successively so as to obtain a series of dilute liquids of various high de grees of dilution.

5 Claims, 4 Drawing Figures PATENTEDJUHIO 1975 SHEET 8 EMZ B PATENTEDJUH 10 1975 PUMP FOR PREPARING DILUTED LIQUIDS OF PREDETERMINED DEGREES OF DILUTION BACKGROUND AND SUMMARY OF THE INVENTION This invention relates to a pump for preparing diluted liquids with desired degrees of dilution, and more particularly to a pump which utilizes a pumping action produced by repetitive compression and blocking of certain sections of a flexible and resilient tube.

An object of the present invention is to provide a pump for preparing diluted liquids of a series of various degrees of predetermined dilution, one after another, in test tubes, through the repetition of compressing, releasing and blocking a flexible and resilient tube at certain portions thereof.

The present invention involves a pumping arrangement for preparing diluted liquids of a series of various degrees of predetermined dilution in which a tube made of a flexible and resilient material opens at its up stream end into a container of diluting liquid and is provided at its other end with a fine charging tube. A branch tube having a pipette at its downstream side end is branched off from the first-mentioned tube at the base portion thereof. Blocking and discharging structures are provided for blocking and compressing certain portions of the first-mentioned tube along the tube length.

Continuing, the present invention provides a pumping arrangement for preparing diluted liquids ofa series of various degrees of predetermined dilution. Two sets of discharging structures are provided along the tube for pressing two parts of the tube, and the rate of length between the parts of the tube to be compressed by the respective discharging structure is varied to effect dilution.

BRIEF DESCRIPTION OF THE DRAWINGS Novel features and advantages of the present invention in addition to those mentioned above will become apparent to those skilled in the art from a reading of the following detailed description in conjunction with the accompanying drawings wherein similar reference characters refer to similar parts and in which:

FIG. 1 is a plan view of a pumping arrangement, according to the present invention;

FIG. 2 is a front elevational view of the arrangement shown in FIG. 1;

FIG. 3 is a perspective view illustrating the driving mechanism for the downstream blocking structure of the present invention; and

FIG. 4 is a graph illustrating the patterns of consecu tive operations of the moving components of the pumping arrangement.

DETAILED DESCRIPTION OF THE INVENTION Referring in more particularity to the drawings, reference character I indicates a fixed flat plate of plastic, and T denotes a tube made of a resilient and flexible plastic material such as silicon resin. Other essential parts of the pumping arrangement of the present invention include first upstream blocking means P second upstream blocking means P discharging means P P and downstream blocking means P Branching off from tube T is a branch tube T which extends upwardly therefrom through a hole H provided at a location in the flat plate I downstream of the first upstream blocking means P A container FL ofa diluting liquid is supported by a stand D, as shown. The extreme upstream end of the tube T is submerged in the diluting liquid in the container FL. The tube T, after passing the downstream extremity of the flat plate I bends upwardly and then extends horizontally in the downstream direction. Finally, the tube bends downwardly, as shown in FIG. 2, and the extreme downstream end of the tube is connected to a fine charging tube N disposed immediately above one of the test tubes 1, arranged circumferentially on a turntable Ta, as shown in FIG. I.

The branch tube T, after passing upwardly through the hole H, extends along a path similar to the tube T, and the downstream extremity of the branch tube T is connected to a pipette C disposed above a test tube t The turntable Ta is provided with recesses for erecting the test tubes therein and the turntable is connected to a ratchet Ra through a shaft Sh. The ratchet Ra is adapted to turn the turntable Ta intermittently to deliver the test tubes r pitch-by-pitch.

The height of the stand D is preset such that the level of the diluting liquid in the container FL will always be positioned substantially at a point halfway between the uppermost end of the upwardly by-passing portion of the branch tube T' and its lowest end even if the level is changed with consumption of the liquid.

The first upstream blocking means P is disposed beneath the tube T at a portion thereof which is positioned upstream of the hold H in the flat plate I. The blocking means P is positioned by being sandwiched with guide plates S,S fixed on both the upstream and downstream sides thereof. Also, the blocking means P has a sharp linear edge at its uppermost end perpendicular to the tube T. The upstream blocking means P moves up and down in accordance with movement of an eccentric rotor E, secured to a shaft M, such that the means P will press the tube T when it is raised up to its operative position. Pressing of the tube T stops when the means P is allowed to descend by gravity.

Each of the upstream blocking means P, and the downstream blocking means P is also provided at its top end with a sharp linear edge perpendicular to the tube T, as shown in FIG. 2. Each is arranged such that when raised to its operative position, it will press and block a minute portion of the tube T, and when lowered to its non-operative position, it will release the tube.

The discharge means P is flat at its top surface, and the length of its flat top surface is determined depending on the amount of fluid to be discharged in one operation. Thus, when the discharge means P is raised, it presses the tube T along the length thereof equal to the length of the top surface of the discharge means to discharge the fluid by an amount about equal to the fluid which is present in the compressed section of the tube T. An eccentric rotor similar to that used for the first upstream blocking means P is employed for actuation of each of the upstream blocking means P,, discharge means P and downstream blocking means P However, two interlocked eccentric rotors are used for moving the discharge means P Another discharge means P is provided between the second upstream blocking means P, and the hole H. This upstream discharge means P, is identical in construction with the discharge means P B, and B are bars adapted for raising or lowering the fine charging tube N in accordance with movement of an eccentric rotor E, so as to lower or lift the fine tube N into or out ofa test tube. One end of the bar 8,, is secured at a point to the tube T above the fine tube N and the other end G, of the bar is fixed to serve as a fixed fulcrum. A point G joined to the bar B, is arranged to serve as a movable fulcrum. The lower end of the bar 8, is secured to a ring R fitted on the eccentric rotor E so as to be movable up and down while sliding on the surface of the rotor E, in accordance with rotation thereof thereby providing an up and down movement to the bar 8,.

Bars 8;, and B are also adapted to operate similarly to the bars B, and B with a point G, acting as a fixed fulcrum to move the pipette C up and down. However, it is not always necessary to lower the end of the pipette C down to a point close to the bottom of the test tube. Instead, there are cases where it is required to only lower the pipette end only to a middle point of the test tube and to inhibit further descent thereof. In such cases, a bar B, attached to an eccentric rotor E is moved up and down such that when the bar B is raised up it touches the bar B, to inhibit further descent of the pipette C. Joint X is adapted to allow elongation of the bar B, when descent of the bar 13 is restricted by the bar 8 Ratchet Ra is adapted to turn the turntable Ta intermittently by a pawl attached to a bar B in accordance with movement of an eccentric rotor E,, so as to deliver one by one the test tubes t arranged upright on the turntable.

Referring now to FIG. 3, a driving mechanism is shown for moving the downstream blocking means P up and down through the medium of an eccentric rotor E,. F, indicates chains, and H,, 1,, 1,, K, and L, denote sprockets having the same diameter and the same number of teeth. The sprockets H, are connected to a reduction motor through a shaft 0 so as to maintain a constant speed throughout operation of the present apparatus. L,, J, and L, are guide sprockets adapted to support the chains which move in accordance with rotation of the sprockets H,. A shaft M passes through the sprockets K, and the eccentric rotor E,. The eccentric rotor E, is secured to the shaft M, but since the sprockets K, are not secured thereto, they are always idling in accordance with movement of the chains. Also mounted fixedly on the shaft M, and in contact with the sprockets K, is another sprocket N, which is the same in diameter as the sprocket K, but which is devoid of teeth except for a pair of diametrically opposed teeth.

The chains F have proturberances located at desired positions thereon. These protuberances move with movement of the chains and are arranged such that when one of the protuberances arrives at a location touching a tooth of the sprocket N the former pushes the latter to allow it to turn 180 thereby causing the eccentric rotor E, to also turn [80 through the shaft M,. Thus, if the eccentric rotor E, is set to normally keep the downstream blocking means P in its nonoperative position and if the sprocket N is secured to the shaft M with its teeth properly orientated. when the downstream blocking means P is raised up to its operative position by rotation of the eccentric rotor E,, the particular protuberance on the chains F, comes off the engaged tooth of the sprocket N, whereby the eccentric rotor E, is stopped in its rotation and brought into a stand-by condition while leaving the downstream blocking means P in its operative position. In this way. both the sprocket N, and the eccentric rotor E, are urged to make half rotation upon every passage of the chain protuberance through the position of the sprockets K thereby switching the position of the downstream blocking means P into the operative and non-operative positions alternately. Therefore, if a desired even number of protuberances are located at the desired positions on the chains, it is possible to infinitely repeat the operation of changing the position of the downstream blocking means P, by a desired number of times within a desired period of time in one cycle of chain movement.

Similar driving means are also provided separately to the respective eccentric rotors E, to E,, adapted for operating the associated means P P P,, P P N, C and Ra. All of these driving means are rotated synchronously with the sprockets 11, through the respective sprockets H, to H,, which are secured to the same shaft 0. Just as the sprockets H, are connected with other sprockets 1,, J-,, K,, L, by the same chain, the respective sprockets H, to H,, associated with the eccentric rotors E, to E,, are connected with other sprockets l,, 1,, l(,, L,; I .1 K,., L,; l,,, J,,, K,,, L,,, by the individually same chains. It is to be noted that respective sprockets l, to l,, are also coaxial with one another as all the sprockets H, to H,, are secured to the same shaft 0, so that even if the positions of the sprockets K, to K,, are different from one another, all of the chains are equal in length. Therefore, if protuberances are located at desired locations not only on the chain F, but also on other chains, it is possible to operate the respective blocking means P P,, P,,, the discharge means P P the pipette C, the fine charging tube N and the ratchet Ra with the rotation of the shaft 0 at desired timing in desired sequences in one cycle of operation. It is of course possible to repeat such cycle of operation continuously.

In operation of the pump for preparing diluted liquids of the prsent invention, first a part of the branch tube T is closed by pinching it with the fingers, for example, and then the apparatus is run whereby the means P,. P and P are actuated to operate as a pump in the manner described below.

That is, first the upstream blocking means P,, discharge means P and downstream blocking means P are closed one after another in the above-described order and the upstream blocking means P, and the discharge means P are opened, whereby the liquid in the container FL is induced out to flow down into the tube T from its upstream to downstream side filling the portion of the tube T above the discharge means P Thereafter the upstream blocking means P,is closed simultaneously with opening of the downstream blocking means P, and then the discharge means P is operated to cause the liquid in the tube portion above the discharge means P to flow further downstream of the tube T. In this way, a predetermined amount of liquid is fed from the upstream side to the downstream side of the tube T.

If the pinch on the tube T by the fingers is released after the liquid flowing from the container FL has filled the tube T, the liquid is allowed to flow into the branch tube T to a height substantially the same as the liquid level in the container FL according to the principle of a siphon. Then, the pump means is again and again operated to fill both the tube T and the fine charging tube N to its foremost end with the liquid. Finally, the test tubes t I I are set on the turntable in the arrangement shown in FIG. 1 with the leading test tube t alone being filled with a solution of specimen, thus completing preparation for the operation.

FIG. 4 is a diagrammatical graph showing the operations of the respective components of the pump arrangement. It will be noted that one cycle of operation consists of 27 steps of continuous motions.

In FIG. 4, the numerical figures arranged horizontally represent the respective step numbers, and the bent cross lines for the respective stages of P P C signify the pattern of motions of the respective components. That is, the line section extending along the raised level shows that the associated component is in its raised position, and the line section extending along the low level shows that the associated component is in its lowered postion. The upward or downward level section of each line indicates that the associated component is being raised or lowered correspondingly. The line for the pipette C alone has a middle level section which shows that although the end of the pipette C is inserted into the test tube, the pipette end is maintained at a height spaced from the liquid level in the test tube. Adjustment of this height of the pipette end is made with operation of the bar B shown in FIG. 2, but such operation of the bar 3;, is not shown in FIG. 4. An arrow mark in the column ofTa in FIG. 4 signifies that the turntable Ta mades a step of turning motion at the step denoted with the arrow mark.

In the following. the operation or movements of the respective components are itemized in the order of steps. Numbers given in the following are those of the steps.

No. 1 This is the preparatory stage before starting. Of the five pumping means P,,, P P P and P the downstream blocking means P alone is in its raised blocking position. The fine tube N and the pipette C are also in their raised positions.

No. 2 The upstream blocking means P, is raised.

No. 3 The fine tube N descends into the test tube and simultaneously the downstream blocking means P also moves down thus producing a condition ready for pouring of diluting liquid.

No. 4 The discharge means P is raised thereby forcing the diluting liquid out into the test tube 1,.

No. 5 The downstream blocking means P is raised to block the downstream side of the tube T.

No. 6 The fine tube N is raised away from the test tube.

No. 7 The first upstream blocking means P is raised to block an endmost upstream portion of the tube T and at the same time the upstream blocking means P is lowered thus completing preparation for pipetting with the pipette C.

No. 8 The upstream discharge means P is pushed up to raise the liquid level in the branch tube T' thereby discharging air in the pipette C by an amount corresponding to the amount of compression given to the tube T by the upstream discharge means P No. 9 The pipette C is inserted into the specimencontaining test tube t to a point close to the bottom thereof.

Nos. 10, 11, l2, l3 and 14 The upstream discharge means P repeats its up and down movements to mix the specimen in the test tube Such a mixing-bystirring step is unnecessary in the first cycle since the specimen per se in the test tube t is initially homogeneous, but in the second and succeeding cycles such a mixing-by-stirring step is required continuously to mix the diluting liquid and specimen.

No. [5 The pipette C rises to a middle point of the test tube with the end of the pipette C separating away from the liquid level.

Nos. 16 and 17 The liquid in the test tube t is once discharged out. As it is liable that air bubbles have entered the pipette or that liquid should have been charged in excess into the pipette during mixing operations in the steps are numbered ID to 14, the liquid in the pipette C must be once completely discharged out. For this purpose, the upstream blocking means P and the upstream discharge means P are raised in succession to ensure perfect discharge of liquid.

No. 18 The upstream blockng means P, is lowered.

No. 19 The pipette C descends to the bottom of the test tube t No. 20 The upstream discharge means P is lowered to cause the pipette to newly suck the liquid in test tube t correctly.

No. 2] The pipette C is now raised in an upward direction.

No. 22 The turntable Ta is turned to bring the test tube to the position beneath the fine tube N and the test tube 1, to the position beneath the pipette C.

No. 23 The pipette C is lowered to a middle point of the test tube t Nos. 24 and 25 The upstream discharge means P and the upstream blocking means P, are raised to effect perfect discharge of liquid into the test tube 1,. In these steps, the specimen liquid in the test tube t is merely added into the diluting liquid which has been poured into the test tube I in step No. 4. and no stirring is made. Such stirring is performed in step Nos. 10 to 14 of the next cycle.

No. 26 The pipette C is raised.

No. 27 All ofthe means P P P, and P are lowered to stand ready for the next cycle of operation.

Through repetition of the above cycle of operations, it is possible to obtain the first diluted liquid with certain times of dilution in the test tube n. the second diluted liquid with greater times of dilution in the test tube and the third diluted liquid with still greater times of dilution in the test tube t;,. In this way, a series of diluted liquids with successively greater times of dilution are obtained in the succeeding test tubes.

lfthe two discharge means P and P are of the same discharging capacity, 2-times dilution can be made in one stage, and if the discharge means P is double the upstream discharge means P in length, 3-times dilution can be obtained in one stage. It is thus possible to make dilution of any desired times by changing the length ratio between the discharge means P and P In the embodiment shown. purely mechanical arrangements are used for all of the driving means. These arrangements are advantageous in minimizing likelihood of causing troubles, but it is also possible to drive the operating means electrically by using solenoid coils.

As described above, the present invention makes use of the phenomenon that if a tube made of a flexible and resilient material such as silicon resin is pressed along a certain length thereof on a flat plate, the liquid in the tube is discharged out with extremely high accuracy in amount. Also when such pressing is removed, the liquid is drawn into the tube with high accuracy in amount.

Further, in the present invention, the means for blocking the tube or the means for pressing it along a certain length thereof are operated in a predetermined order to produce a pumping or pipetting action in cooperation with the tube. Also, if desired, such pumping or pipetting operation may be inversely effected, so that it is possible to obtain a pump for preparing dilute liquids of a series of various degrees of predetermined dilutionsr What is claimed is:

l. A pumping arrangement for preparing diluted liquids of a series of various degrees of predetermined dilution comprising a main tube of flexible and resilient material open at its extreme upstream end into a container of diluting liquid and its other end terminating with a fine charging tube, a branch tube extending from a base portion of the main tube provided at its extreme downstream end with a pipette. first upstream blocking means connected to block the main tube at a location upstream from the point of connection of the branch tube, second upstream from the point of connection of the branch tube, second upstream blocking means located downstream from the point of connection of the branch tube for blocking the main tube, and discharge means located adjacent the second upstream blocking means for pressing the main tube along a predetermined length thereof, and driving means for feeding test tubes successively one by one to the positions immediately below the pipette and the fine charging tube.

2. A pumping arrangement as in claim 1 wherein the discharge means includes a pair of platens for pressing the main tube and the platens are positioned on opposite sides of the second upstream blocking means.

3. A pumping arrangement as in claim 1 wherein the fine charging tube provided at the extreme downstream end of the main tube and the pipette provided at the extreme downstream end of the branch tube are movably mounted for up and down motion relative to the test tubes which are successively fed to the positions below the fine charging tube and the pipette.

4. A pumping arrangement as in claim 1 wherein a turntable is disposed below the pipette and the fine charging tube, the turntable carrying thereon a plurality of test tubes arranged equidistantly along the same circumference, and means for rotating the turntable step by step corresponding to the pitch of the array of the test tubes.

5. A pumping arrangement as in claim 1 including driving means (l) for operating the blocking means and the discharging means, (2) for raising and lowering the fine charging tube and the pipette, and (3) for rotating the test tubes all in predetermined sequence to thereby prepare in the test tubes the dilute liquids of a series of various degrees of predetermined dilution.

* fll 

1. A pumping arrangement for preparing diluted liquids of a series of various degrees of predetermined dilution comprising a main tube of flexible and resilient material open at its extreme upstream end into a container of diluting liquid and its other end terminating with a fine charging tube, a branch tube extending from a base portion of the main tube provided at its extreme downstream end with a pipette, first upstream blocking means connected to block the main tube at a location upstream from the point of connection of the branch tube, second upstream from the point of connection of the branch tube, second upstream blocking means located downstream from the point of connection of the branch tube for blocking the main tube, and discharge means located adjacent the second upstream blocking means for pressing the main tube along a predetermined length thereof, and driving means for feeding test tubes successively one by one to the positions immediately below the pipette and the fine charging tube.
 2. A pumping arrangement as in claim 1 wherein the discharge means includes a pair of platens for pressing the main tube and the platens are positioned on opposite sides of the second upstream blocking means.
 3. A pumping arrangement as in claim 1 wherein the fine charging tube provided at the extreme downstream end of the main tube and the pipette provided at the extreme downstream end of the branch tube are movably mounted for up and down motion relative to the test tubes which are successively fed to the positions below the fine charging tube and the pipette.
 4. A pumping arrangement as in claim 1 wherein a turntable is disposed below the pipette and the fine charging tube, the turntable carrying thereon a plurality of test tubes arranged equidistantly along the same circumference, and means for rotating the turntable step by step corresponding to the pitch of the array of the test tubes.
 5. A pumping arrangement as in claim 1 including driving means (1) for operating the blocking means and the discharging means, (2) for raising and lowering the fine charging tube and the pipette, and (3) for rotating the test tubes all in predetermined sequence to thereby prepare in the test tubes the dilute liquids of a series of various degrees of predetermined dilution. 